Field
Embodiments of the invention relate to scanning beam devices. In particular, embodiments of the invention relate to calibration of scanning beam devices.
Background Information
Various types of scanning beam devices are known in the arts and described in the literature. One type of scanning beam device is a scanning fiber device. The scanning fiber device may include a single, cantilevered optical fiber.
In one aspect, the scanning fiber device may be used to acquire an image of a target area. In acquiring the image of the target area, the single, cantilevered optical fiber may be vibrated in order to scan an illumination spot through an optional lens system and over the target area according to a scan pattern. Backscattered light may be captured, for example by a photosensor, in time series.
In acquiring the image, it generally helps to accurately know the position of the optical fiber and/or the illumination spot throughout the scan. Knowing the drive signal that is used to scan the optical fiber may allow the position of the illumination spot to be estimated for each pixel point in time during the scan pattern. In practice however, environmental variables, manufacturing variables, imperfect electronics, the sensitivity of the scanning fiber device around the resonance frequency, and/or other factors, may tend to limit the accuracy of such estimates. Such positional inaccuracies may also tend to exist in other types of scanning beam devices besides just scanning fiber devices.
If unaccounted for, such positional inaccuracy may tend to add distortion to the image generated using the scanning fiber device.